I live in south central Arizona and have a back yard of about 2 acres. Our yard has a typical Arizona--California block wall around it about 7 feet high. My mallards have a large pen about 20x25, are about 3 months old and happy where they are. They are now flapping their wings and wanting to fly. Should I let them out of the pen during the day time to wonder around or will they take off and go elsewhere, maybe even to the neighbors pool. Any advise from you Mallard folks will be much appreciated.